Though he was Jewish, Hildebrand Gurlitt was an art dealer approved by the government of Nazi Germany. During World War II, he collected and privately hoarded approximately 1,280 works of art, most of them looted from Nazi-occupied nations. This was a huge number. For comparison, consider that the National Gallery in London has only 2,000 pieces.

Hildebrand Gurlitt survived the war and kept his collection a secret. As he was dying in 1956, he gave his 24-year old son Cornelius Gurlitt the duty of maintaining this collection. The younger Gurlitt did so. He never married and was a recluse after his parents and sister died. He was devoted to one task: keeping the huge art collection a secret inside his apartment in Munich.

Cornelius Gurlitt kept everyone out of his dingy apartment, cramped with great works of art, until 2012. Then police searched his home after he was caught trying to bring a large amount of cash into Switzerland. Gurlitt agreed to help government investigators find the owners of the artworks in his collection.